Texas Instruments LP38692MPX-1.8

Overview

LP38692MPX-1.8 from Texas Instruments is a 1-A, 1.8-V fixed-output low-dropout CMOS linear regulator in SOT-223 package, featuring 2.5% output accuracy at 25°C, 950 mV dropout at 1 A (V_OUT = 1.8 V), and enable control for power sequencing in battery-powered digital systems.

For engineers reviewing the LP38692MPX-1.8 datasheet, LP38692MPX-1.8 pinout, LP38692MPX-1.8 application, or LP38692MPX-1.8 equivalent, key selection considerations include dropout voltage at full load, ground pin current (55 µA typical), thermal shutdown threshold (160°C), foldback current limiting behavior, and compatibility with 1-µF ceramic output capacitors.

Technical Context

The LP38692MPX-1.8 uses a PMOS pass transistor to eliminate DC base drive current, enabling ultra-low ground pin current (<100 µA across load, input, and temperature). Its internal trimmed bandgap reference and feedback loop ensure stable regulation over –40°C to 125°C.

Enable functionality is implemented via a logic-level EN pin with no internal pull-up/down; activation requires V_EN ≥ 1.8 V (at VIN = 4 V) and deactivation occurs below 0.4 V. Foldback current limiting responds dynamically to VIN–VOUT differential: limits to ~450 mA when ΔV > 5 V, and ~1500 mA when ΔV < 4 V.

Key Specifications

Pinout & Package

SOT-223 (NDC) 5-pin thermally enhanced package with exposed pad (DAP) for PCB heat sinking; pin 1 = IN, pin 2 = GND, pin 3 = OUT, pin 4 = SNS (not connected on LP38692MPX-1.8 per datasheet), pin 5 = EN.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPL7407LPGP and TPS7A0518PDBVR, the LP38692MPX-1.8 uniquely delivers 1-A output with enable control and ceramic-capacitor stability in SOT-223 - making it suitable for higher-current portable systems where TPL7407LPGP lacks standalone regulation capability and TPS7A0518PDBVR cannot sustain full-load current.

Availability

LP38692MPX-1.8 is available at Aetrix Electronics and suitable for hard disk drives, notebook computers, and battery-powered devices requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for LP38692MPX-1.8 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in power management ICs and high-reliability analog solutions.

The LP38692MPX-1.8 belongs to TI's LP3869x family of low-dropout linear regulators, designed specifically for portable, battery-powered digital systems demanding accurate voltage, fast start-up, and ultra-low quiescent current.

FAQ

What is the minimum input voltage required for LP38692MPX-1.8 to regulate 1.8 V output?

The LP38692MPX-1.8 requires VIN ≥ (V_OUT + V_DO). At 1 A load and 25°C, its dropout voltage is 950 mV - so minimum VIN is 2.75 V. The device specifies a wider operating range of 2.7 V to 10 V, but regulation begins only when VIN exceeds V_OUT plus actual dropout, which increases with temperature and load. LP38692MPX-1.8 does not include UVLO; internal circuitry becomes functional above 2.7 V.

Does LP38692MPX-1.8 require an external pull-up resistor on the EN pin?

Yes - the EN pin has no internal pull-up or pull-down. It must be actively or passively terminated. For always-on operation, connect EN directly to IN. For controlled enable/disable, use a logic-level signal referenced to GND with drive strength sufficient to exceed V_EN(ON) ≥ 1.8 V (at VIN = 4 V) and fall below V_EN(OFF) ≤ 0.4 V. Leaving EN floating risks undefined output state and potential malfunction. This applies specifically to LP38692MPX-1.8 due to its enable functionality.

Can LP38692MPX-1.8 operate with a 1-µF ceramic output capacitor?

Yes - LP38692MPX-1.8 is explicitly characterized and specified for stability with a minimum 1-µF ceramic output capacitor (X5R/X7R), eliminating ESR requirements. This is enabled by its PMOS architecture and internal compensation. The datasheet confirms stable operation with C_OUT = 1 µF, unlike many older LDOs requiring tantalum or aluminum electrolytics with specific ESR. LP38692MPX-1.8 achieves this across –40°C to 125°C.

What is the thermal shutdown behavior of LP38692MPX-1.8?

LP38692MPX-1.8 activates thermal shutdown at approximately 160°C junction temperature and resumes regulation after cooling to ~150°C (10°C hysteresis). During sustained overload, it may cycle on/off to limit average power dissipation. This protects against permanent damage but is not a substitute for proper thermal design - continuous cycling degrades reliability. The SOT-223 package has R_θJA = 68.5°C/W; actual junction temperature depends on PCB copper area and ambient conditions. LP38692MPX-1.8 includes no user-accessible thermal flag.

Is the SNS pin used on LP38692MPX-1.8 in SOT-223 package?

No - the SNS (sense) pin is not used on LP38692MPX-1.8 in SOT-223 package. Per the official datasheet Pin Functions table, SNS is designated "-" for LP38692 in SOT-223, and the simplified schematic for LP38692 shows SNS as unconnected in that variant. Remote sensing is supported only in WSON packages. On LP38692MPX-1.8, the SNS pin (Pin 4) must be left unconnected or tied to OUT only if required by layout constraints - it has no functional role in regulation.